Clip for heat sink

1. A clip for mounting a heat sink on a circuit board, the heat sink comprising a base and a plurality of fins extending perpendicularly from a top face of the base, the clip comprising: a positioning coil configured for rotatably engaging with the heat sink and abutting against the top face of the base, the positioning coil comprising two ends; two elongated arms extending from the two ends of the positioning coil respectively, wherein each of the arms comprises a straight portion directly connected to the positioning coil and extending straight up relative to the top face of the base, the length of the straight portion is generally equal to the height of the fins, thereby avoiding interfering with the fins when the positioning coil rotates relative to the heat sink; and a pair of hooks formed at distal portions of the two arms respectively for engaging with the circuit board.

2. The clip as claimed in claim 1 , wherein projecting lines of the arms on the plane formed by the positioning coil extend away from the positioning coil in opposite directions on parallel paths.

3. The clip as claimed in claim 1 , wherein the two ends of the positioning coil are located at opposite ends of a bisecting line of the positioning coil.

4. An assembly comprising: a heat sink defining an annular slot; a circuit board comprising an electronic component and a pair of securing members mounted thereon; and a clip for mounting the heat sink to the electronic component; the clip comprising a positioning coil rotatably engaging in the slot of the heat sink and retained to the bottom of the slot, and two elongated arms extending from two ends of the positioning coil located at a bisecting line of the positioning coil respectively, for engaging with the securing members respectively, wherein each of the arms comprises a straight portion directly connects to the positioning coil, extending straight up from the bottom of slot, and has a length generally equal to the depth of the slot to prevent the arms from interfering with the fins when the positioning coil rotates in the slot.

5. The assembly as claimed in claim 4 , wherein the heat sink includes a base having a bottom face thermally contacting with the electronic component, a plurality of fins extending upwardly and perpendicularly from a top face of the base, the slot is defined in the fins.

6. The assembly as claimed in claim 5 , wherein each of the two arms further comprises a slant portion extending from a distal end of the straight portion and slanting upwardly relative to a plane formed by the positioning coil, projecting lines of the arms on the plane formed by the positioning coil extending away from the positioning coil in opposite directions on parallel paths.

7. The assembly as claimed in claim 4 , wherein two hooked flanges are formed on the top face of the base and located at opposite sides of the slot, for holding the positioning coil of the clip to the heat sink.

8. The assembly as claimed in claim 4 , wherein each of the securing members includes a catch thereon, and a pair of hooks is formed at distal portions of the two arms respectively, the hooks positioning coil are locked into corresponding catches of the securing members with the two arms being deformed to exert force on the positioning coil thereby holding the heat sink in reliable contact with the electronic component.

9. The assembly as claimed in claim 4 , wherein the clip is made of a wire.

10. An assembly comprising: a circuit board comprising an electronic component and a pair of securing members mounted thereon; a heat sink placed on the electronic component, the heat sink defining an annular slot; and a clip for securing the heat sink to the electronic component, the clip being integrally made of a wire and comprising a positioning coil engaged in the slot of the heat sink in such a manner that the positioning coil is rotatable relative to the heat sink in a plane defined by the positioning coil and is fixed relative to the heat sink in a direction perpendicular to the plane, and two elongated arms respectively extending from two ends of the positioning coil located at a bisecting line of the positioning coil, the arms being depressable to deform and engage with the securing members respectively; wherein each of the arms comprises a straight portion directly connected to the positioning coil and extending straight up relative to the plane, and a slant portion extending from a distal end of the straight portion slantingly upwardly relative to the plane formed by the coil.

11. The assembly as claimed in claim 10 , wherein each of the securing members comprises a catch, and a pair of hooks is formed at distal portions of the two arms respectively, the hooks capable of interlocking with the respective catches via depressing the two arms which results in the two arms being deformed to exert a force on the positioning coil toward the electronic component thereby holding the heat sink in reliable contact with the electronic component.

12. The assembly as claimed in claim 10 , wherein the heat sink comprises a base and a plurality of fins extending up from the base, the slot is defined in the fins above the base, and two hooked flanges extend up from the base and then bent toward the base configured to hold the positioning coil of the clip in the slot such that the positioning coil is rotatable relative to the heat sink in the plane defined by the positioning coil and is fixed relative to the heat sink in the direction perpendicular to the plane.